The Allen-Bradley 1746-IB16, also cataloged as the 1746-IB16 Digital Input Module, operates as a dedicated hardware component for discrete DC signal processing within Allen-Bradley SLC 500 rack platforms.
Hardware Specifications
Parameter
Specification
Model
1746-IB16
Brand
Allen-Bradley
Origin
USA
Weight
0.88 lbs (0.40 kg)
Dimensions
Standard SLC 500 Single-Slot Module Width
Operating Temp
0 to 60 deg C
Power Consumption
0.25 W (5 VDC backplane draw)
Number of Inputs
16 Inputs
Input Type
Current Sinking
Voltage Category
24 VDC (10-30 VDC operating range)
Backplane Current (5 VDC)
0.05 A
Backplane Current (24 VDC)
0 A
Maximum Signal Delay
8 ms (ON/OFF transition)
Total Heat Dissipation
3.6 W
Heat Dissipation per Point
0.2 W
Minimum Heat Dissipation
0.425 W
Terminal Block
Removable Terminal Block Included
Backplane Bus Communication Velocity & I/O Density Scaling
The 1746-IB16 interface card maintains deterministic backplane bus communication velocity by scanning 16 discrete channels via backplane logic level transitions at a minimal current draw of 0.05 A at 5 VDC. High I/O density scaling is achieved through 16 current-sinking input circuits designed for 24 VDC discrete field devices. The module incorporates optoelectronic channel-to-backplane isolation to suppress field-side electromagnetic interference, while limiting maximum signal propagation delays to 8 ms across all channels to optimize real-time controller throughput.
Frequently Asked Questions
Q: What is the backplane current draw of the 1746-IB16 on the 24 VDC rail?
A: The 1746-IB16 draws 0 A from the 24 VDC backplane bus, relying solely on 0.05 A from the 5 VDC backplane rail to power its internal logic components.
Q: Does the 1746-IB16 module require powering down the rack to change terminal wiring?
A: No, the module includes a removable terminal block (RTB) that allows field wiring to be disconnected and serviced without altering the physical backplane slot alignment or backplane connector integrity.
Field Installation Guidelines
Align the circuit board with the top and bottom chassis card guides, pushing the module firmly into the vacant SLC 500 slot until the securing latches click.
Wire field input devices to the removable terminal block observing correct polarity for current-sinking circuits (+24 VDC common to field devices, module terminal acting as current path to ground).
Ensure signal wiring is physically separated from high-voltage AC lines and motor leads to prevent inductively coupled transient noise from causing erratic input transitions.
Verify that field supply wiring stays strictly within the 10-30 VDC operating threshold to prevent premature thermal stress or input channel degradation.
